[Gate-users] missing event IDs in hits file

Tue Feb 1 00:19:49 CET 2011

Dear Simon,

I set the world to tungsten and placed a box of air within it. Then placed the SPECThead (macro given below). Also, like you said, I estimated the proportion of missing ids. With this, I got a hits file in which the maximum eventID was 37226 with 4627 unique IDs. 

Originally, with a pixelated crystal as detector, the maximum eventID was 3589, but there were only 428 unique eventIDs (same ratio as above).  When a continuous crystal detector was used, the maximum eventID was 62825 with 26346 unique IDs (a much better ratio). 

I can understand that some particles don't hit the detector but with only a single emission angle and nothing but vacuum/air, what could be happening to the particles? 

Thank you,

Ramya

/vis/disable
/gate/geometry/setMaterialDatabase GateMaterials.db
/gate/world/geometry/setXLength 700 mm
/gate/world/geometry/setYLength 700 mm
/gate/world/geometry/setZLength 700 mm
/gate/world/setMaterial Tungsten

/gate/world/daughters/name newbox
/gate/world/daughters/insert box
/gate/newbox/geometry/setXLength 500. mm
/gate/newbox/geometry/setYLength 500. mm
/gate/newbox/geometry/setZLength 500. mm
/gate/newbox/setMaterial Air

/gate/newbox/daughters/name SPECThead
/gate/newbox/daughters/insert box
/gate/SPECThead/geometry/setZLength 60. mm
/gate/SPECThead/geometry/setYLength 100.   mm
/gate/SPECThead/geometry/setXLength 100.   mm

-----Original Message-----
From: Simon Stute [mailto:gate.stute at gmail.com] 
Sent: Monday, January 31, 2011 3:33 PM
To: Rajaram, Ramya (H USA)
Cc: Piotr Mazur; gate-users at lists.opengatecollaboration.org
Subject: Re: [Gate-users] missing event IDs in hits file

Hi all,

Maybe you can try to set the world's material to gold, tungsten, or something heavy, and then create a smaller box inside it, made of air, to actually replace your current world. By doing this, you will have a sort of barrier all around your simulation, that cannot miss any particle. See then if you still get some missing eventID.

Otherwise, what is the proportion of missing eventID you got ? It could give you some hint.

Last point concerning the visualization. If you do not use the accumulate option, you can't use it as a proof. Only with this option, you will see all particles, but it could be difficult when the screen starts to be full of green :-)

Good luck,
Simon

On Thu, Jan 27, 2011 at 10:56 PM, Rajaram, Ramya (H USA) <ramya.rajaram at siemens.com> wrote:

	Hi Piotr,

	I have tried to put the point source at various locations in front of the detector but the problem of missing eventIDs in the hits file still exists. Also, with the visualization commands enabled, it appears that the particles are hitting the detector. So I don't know what is wrong. Could it be somehow related to using pixelated detectors? With a continuous crystal like NaI, I noticed that the eventIDs are much more (yet not completely) continuous.

	Thank you very much for offering to investigate the issue. Please let me know if you get a chance to resolve it.

	Ramya

	-----Original Message-----
	From: Piotr Mazur [mailto:pietrmazur at gmail.com]
	Sent: Thursday, January 27, 2011 3:17 PM
	To: Rajaram, Ramya (H USA)

	Subject: Re: [Gate-users] missing event IDs in hits file

	Hi,

	You are right!! It's not working. I will take a look at this but I
	suppose just as Marlen - all events miss the detector. I will give a
	try to run it, at the same time my hint is to put more attention to
	check whether point source doesn't hit the detector. Other problem is,
	which is also very interesting for me -> isn't it the problem when the
	source is IN the SPECThead?

	I will investigate it further

	Piotr

	On Thu, Jan 27, 2011 at 9:13 PM, Rajaram, Ramya (H USA)
	<ramya.rajaram at siemens.com> wrote:
	> Hi all,
	> Here's the macro that I am running.
	> Thanks,
	> Ramya
	>
	> -----Original Message-----
	> From: Marlen Priegnitz [mailto:m.priegnitz at hzdr.de]
	> Sent: Thursday, January 27, 2011 2:53 AM
	> To: Rajaram, Ramya (H USA)
	> Cc: gate-users at lists.opengatecollaboration.org
	> Subject: Re: [Gate-users] missing event IDs in hits file
	>
	>
	> Hi,
	>
	> Maybe this is, because some events don't hit the detector but leave the
	> "World" without any interaction in sensitive detectors?
	>
	> Kind regards,
	> Marlen
	>
	>
	>
	> Rajaram, Ramya (H USA) wrote:
	>> Dear Gaters,
	>>
	>> I am currently trying to simulate a very simple set-up: a point source
	>> at a certain distance from a detector inside a SPECThead. All the
	>> volumes are attached to either phantomSD or crystalSD. ASCII output is
	>> enabled and in the Hits.dat file that is generated after the simulation,
	>> some eventIDs are missing. Why would that be? I thought eventID is the
	>> one unique and continuous column that helps keep track of all the list
	>> mode information across the Hits, Singles, SinglesAdder,
	>> SinglesBlurring, etc data files. Is that not right?
	>>
	>> Any help is greatly appreciated,
	>>
	>> Thank you,
	>>
	>> Ramya
	>> _______________________________________________
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	>> Gate-users at lists.opengatecollaboration.org
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	>
	> --
	> Marlen Priegnitz             |  Helmholtz-Zentrum Dresden-Rossendorf
	> Tel. : 0351/260 3307         |
	> Fax  : 0351/260 3700         |  Postfach 510119
	> Email: m.priegnitz at hzdr.de   |  D-01314 Dresden
	> ------------------------------------------------------------------------
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